Hydraulic conductance of intact plants of two contrasting sorghum lines, SC15 and SC1205

2013 ◽  
Vol 40 (7) ◽  
pp. 730 ◽  
Author(s):  
Sunita Choudhary ◽  
Thomas R. Sinclair ◽  
P. V. Vara Prasad

Low plant hydraulic conductance has been hypothesised as an approach to decrease the rate of soil water use, resulting in soil water conservation for use during late season water deficits. The impact of leaf hydraulic conductance (Kleaf) on water use characteristics was explored by comparing two sorghum (Sorghum bicolor (L.) Moench) genotypes that had been found to differ in Kleaf. Genotype SC15 had a much lower leaf conductance than genotype SC1205. Four sets of experiments were undertaken to extend the comparison to the impact of differences in Kleaf on the plant water budget. (1) Measurements of hydraulic conductance of intact plants confirmed that leaf conductance of SC15 was lower than that of SC1205. (2) The low leaf conductance of SC15 was associated with a decrease in transpiration during soil drying at a higher soil water content than that of SC1205. (3) SC15 had a restricted transpiration rate at vapour pressure deficits (VPD) above 2.1 kPa, whereas SC1205 did not. (4) Treatment with aquaporin inhibitors showed substantial differences in the sensitivity of the transpiration response between the genotypes. These results demonstrated that low Kleaf in SC15 was associated with conservative water use by restricting transpiration at higher soil water content during soil drying and under high VPD. Tests with inhibitors indicate that these differences may be linked to differences between their aquaporin populations. The differences between the two genotypes indicated that the traits exhibited by SC15 would be desirable in environments where soil water deficits develop.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 549f-550
Author(s):  
Mongi Zekri ◽  
Bruce Schaffer ◽  
Stephen K. O'Hair ◽  
Roberto Nunez-Elisea ◽  
Jonathan H. Crane

In southern Florida, most tropical fruit crops between Biscayne and Everglades National Parks are irrigated at rates and frequencies based on experience and observations of tree growth and fruit yield rather than on reliable quantitative information of actual water use. This approach suggests that irrigation rates may be excessive and could lead to leaching of agricultural chemicals into the groundwater in this environmentally sensitive area. Therefore, a study is being conducted to increase water use efficiency and optimize irrigation by accurately scheduling irrigation using a very effective management tool (EnviroScan, Sentek Environmental Innovations, Pty., Kent, Australia) that continuously monitors soil water content with highly accurate capacitance multi-sensor probes installed at several depths within the soil profile. The system measures crop water use by monitoring soil water depletion rates and allows the maintenance of soil water content within the optimum range (below field capacity and well above the onset of plant water stress). The study is being conducted in growers' orchards with three tropical fruit crops (avocado, carambola, and `Tahiti' lime) to facilitate rapid adoption and utilization of research results.


2020 ◽  
Vol 68 (4) ◽  
pp. 351-358
Author(s):  
Miroslav Fér ◽  
Radka Kodešová ◽  
Barbora Kalkušová ◽  
Aleš Klement ◽  
Antonín Nikodem

AbstractThe aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.


The conservation of water resources through their optimal use is a compulsory for countries with water shortages in the arid and semi-arid regions, and it should be in an environmentally friendly manner to avoid the serious consequences of the use of environmentally harmful substances, the implications of which are currently evident from climate change, pollution of water bodies, soils, etc. Since Egypt is one of those countries suffering from water scarcity and uses about 82.5 percent of its water consumption in agriculture, according to data of the Ministry of Irrigation in 2010, so this research is focusing on the use of new methods to increase the efficiency of irrigation water, to achieve high productivity of agricultural crops with less water use that will certainly help to alleviate or solve the water scarcity issue. The study used a physical based model, to simulate the methods used to increase sand soil properties to ensure larger water retention index. Within this work, soil have been sampled from different areas, to simulate the behavior of arid lands, under different water retention techniques. Soil was exposed to different techniques, as it was mixed with soil additives in different quantities and different types. Physical barriers of cohesive soil and polyethylene sheets were used in addition to studying the effect of mulch on water storage capacity in noncohesive soil. Water retention have been measured using the direct method of determination soil water content by oven drying and the volumetric water content (𝞱v ) with time graphs have been plotted in groups, as well as the cultivated plants have been monitored as to measure the influence on plants growing and irrigation efficiency. And the experiment showed that the use of rice straw (RS) and wheat straw (WS) in the powder condition have a significant effect in increasing in the soil water content and even to the plant growth, the WS obtained 𝞱v values approaching the loam soil at times and slightly less in the case of RS, when the percentage of RC and WS was 30% to the sandy soil volume/volume (v/v). Also the use of mulch of RS showed a noticeable increase in 𝞱v and significant improvement of plant growth to that without mulch. These proven technologies can be used in sandy land targeted for reclamation to reduce water use in agriculture.


2012 ◽  
Vol 226-228 ◽  
pp. 2098-2102 ◽  
Author(s):  
Xin Jing Wang ◽  
Zhen Qi Hu ◽  
Yan Ling Zhao ◽  
Yu Ming Guo ◽  
Pei Jun Wang

Using the ground-penetrating radar (GPR) system with the different frequencies and neutron probe, combing with radar image interpretation and the amplitude spectrum, the impact of GPR detection effects on the soil taxonomy and underground pipe were analyzed. The results indicate that when the soil content is 17.02%, the effect on soil taxonomy of 750MHZ antenna is better than 400MHZ, but the effect on underground pipe is same. As soil water content increases to 25.333%, the soil taxonomy of two antennas’ detection tends to same, and “fake stratifications” existed. The soil water content accelerates to 36.389%, the detection effect on soil taxonomy and underground pipe is so poor. Attenuation mechanism and propagation characteristics of the high electromagnetic wave were presented to interpret those phenomena. The above analysis shows that the soil water content is one of the main prerequisites for the applications of GPR. Some indicators could be provided to nondestructive test in land consolidation project quality by GPR from this research.


2001 ◽  
Vol 50 (2) ◽  
pp. 97-108 ◽  
Author(s):  
Karina M Sakalauskas ◽  
José L Costa ◽  
Pedro Laterra ◽  
Liliana Hidalgo ◽  
Luis A.N Aguirrezabal

2008 ◽  
Vol 48 (3) ◽  
pp. 274 ◽  
Author(s):  
K. L. Greenwood ◽  
G. N. Mundy ◽  
K. B. Kelly

Maize, as a C4 species, is likely to use water more productively than the perennial ryegrass and white clover pastures typically grown for dairy cows in northern Victoria. However, only estimates of water use by irrigated maize crops are available for this region. We measured the growth and water use of three commercial maize crops used for silage in northern Victoria. Crops under centre pivot irrigation were monitored in 2003–04 (Spray 1) and 2004–05 (Spray 2). A border-check irrigated crop (Border-check) was monitored in 2004–05. The Spray 1 crop was irrigated 30 times and received 782 mm of rainfall and irrigation. The crop yielded 22 t DM/ha, giving a water productivity of 28 kg DM/ha.mm (including irrigation, rainfall and change in soil water content). In the cooler, wetter summer of 2004–05, the water productivity was 34 kg DM/ha.mm for the Spray 2 crop and 30 kg DM/ha.mm for the Border-check crop. Crop evapotranspiration was estimated from weather data and a daily soil water balance was computed according to FAO 56. The estimated and measured changes in soil water content were in good agreement and indicated that the basal crop coefficients in the model (Kcb = 1.15 during the mid-season, before correction for non-standard humidity and wind speed) were appropriate to local conditions. Maize grown for silage in northern Victoria has higher water productivity than pastures. However, high yields are required to make it economically viable compared with alternative forages for dairy cows. These data will assist dairy farmers to select the optimum forage mix for their enterprises.


1994 ◽  
Vol 119 (3) ◽  
pp. 383-388 ◽  
Author(s):  
Horst W. Caspari ◽  
M. Hossein Behboudian ◽  
David J. Chalmers

Five-year old `Hosui' Asian pear (Pyrus serotina Rehder) trees growing in drainage lysimeters and trained onto a Tatura trellis were subjected to three different irrigation regimes. Weekly water use (WU) was calculated using the mass-balance approach. Soil-water content of control lysimeters was kept at pot capacity, while deficit irrigation was applied before [regulated deficit irrigation (RDI)] and during the period of rapid fruit growth [late deficit irrigation (LDI)]. Soil-water content was maintained at ≈50% and 75% of pot capacity for RDI and LDI, respectively. Deficit irrigation reduced mean WU during RDI and LDI by 20%. The reduced WU was caused by lower stomatal conductance (gs) on deficit-irrigated trees. RDI trees had more-negative diurnal leaf water potentials (ψl). The ψl, gs, and WU remained lower for 2 weeks after RDI was discontinued. RDI reduced shoot extension and summer pruning weights, whereas winter pruning weights were not different between treatments. Except for the final week of RDI, fruit growth was not reduced, and fruit from RDI grew faster than the control during the first week after RDI. In contrast, fruit volume measurements showed that fruit growth was clearly inhibited by LDI. Final fruit size and yield, however, were not different between treatments. Return bloom was reduced by RDI but was not affected by LDI.


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